Fuse



T. B. DOE EI'AL N ov.4 7 1944.

FUSE

Filed Aug.' 8. 1940 2 Sheets-Sheet 1' INVENToRs ThomasRDaeRoertLKenngott s. afd. .fffff w i Nov. 7, 1944. 'r. B. DOE ErAl.

FUSE Filed Aug. 8, l1940 2 S'heets-Sl'lee 2 Hlliliih NTO 5 50 mm$SB.D0ez/Rober Jnngol' ATTORNEY Patented Nov. 7, 1944 FUSE Thomas B. Doe and Robert L. Kenngott, New

York, N. Y., assignors to Ford Instrument Company, Inc., Long Island City, N. Y., a corporation of New York Application August 8, 1940, Serial No. 351,893

` 6 claims.

This invention relates to fuses for projectiles and more particularly to fuses for detonating a projectile at a selected point in its night.

An object of the invention is to provide such a fuse for a projectile whichI functions upon the projectile being retarded to a Velocity corresponding to a selected point in its night. Another object of the invention is to provide a fuse for a projectile in which ,a predetermined difference in pressure between the air pressure on the nose of the fuse and a predetermined air pressure set in a sealed chamber within the fuse causes the fuse to function.

Another object of the invention is to provide a fuse for a projectile in which the firing pin or hammer, which is held in an inoperative condidrawings in which;

Fig. 1 is a vertical cross-sectional view of an embodiment of the invention taken on line I--l of Fig. 8;

Fig. 2 is a view similar to Fig. 1 but taken at right angles thereto, on line 2-2 of Fig. 9;

Fig. 3 is a view in elevation of a cross passage valve;

Fig. 4 is a horizontal, partial cross-sectional view taken on line 4--4 of Fig. 1;

Fig. 4a is a horizontal, partial cross-sectional View taken on line lla-4a of Fig. 2;

Fig. 5 is a view in elevation of a stop;

Fig. 6 is a horizontal partial cross-sectional view taken on line 6--6 of Fig. 1;

Fig. 7 is a horizontal partial cross-sectional view taken on line 1--1 of Fig, 1;

Fig. 8 is a horizontal cross-sectional view taken on line 8-8 of Fig. 1; and

Fig. 9 is a horizontal cross-sectional View taken on line 9--9 of Fig. 1.

In many of the fuses in use heretofore a powder train leading from a firing cap to the detonating charge in the projectile is ignited at the time the projectile is fired and burns to the detonating charge of the projectile in an interval of time depending on the point of ignition of the powder train. These fuses not only require that there be placed in the fuse itself a considerable amount of powder, which must be manufactured with care that the rate of propagation of the flame be known and constant, but their construction has been such that they also require that the powder train be assembled with the fuse at the factory,

with the attending dangers during assembly, shipment and storage.

To overcome these disadvantages, the present invention provides a fuse which may be manufactured, shipped and stored without any powder or detonating caps therein. The loading of the fuse with powder and the insertion of the iiring caps are such simple operations that they may be done just before securing the fuse on the projectile.

The fuse of the present invention is iired by a iiring pin or firing hammer which is moved by centrifugal force acting upon the hammer mass, the hammer being held in a fixed position by a detent until the desired time of detonation. This detent is pulled out of engagement with the hammer when the' projectile has reached a selected point in its night.

It iswell known that the air pressure on the nose of a projectile varies with the velocity of the projectile and the conditions of the atmosphere through which it passes and that the velocity of the projectile Varies with the time of flight and the angle of elevation until the projectile has reached its maximum height in the trajectory. Data for the various sizes of projectile and initial velocities are well known and are available in easily interpretable tablesand curves.

To release the detent there is provided an opening in the nose of the fuse which is placed in communication with one side of a diaphragm after the projectile has left the gun, the other side of which diaphragm is in communication with an air chamber in the fuse in which has been sealed air at a selected pressure. The detent is connected to the diaphragm `and releases the hammer when the nose air pressure is reduced to an amount such that the diaphragm is moved under the pressure of the air in the sealed chamber. The required pressure in the sealed chamber is determined by the range at which it is desired that the projectile be detonated and the difference in pressure on the two sides of the diaphragm that is necessary to snap it over from one position to another. With the type of diaphragm used in one construction, a difference of pressure of ten pounds per square inch was found necessary to snap over the diaphragm from one position to another. Thus if it is desired to detonate the projectile at a range corresponding to a nose pressure of seventy-five pounds per square inch, the sealed air chamber would be charged to a pressure of eighty-five pounds per square inch.

It will therefore be seen that when the projectile has reached the desired range, the diaphragm will be snapped over and the firing Yhammer 5.

shell about its central axis.

It is 4realizedthat other fuses have been disclosed whose functioning depends upon the balancing of the nose air pressure due to the velocity of .the projectile against the reaction of springs or the centrifugal force due to the masses of certain parts of the fuse. These mechanical parts are subject to disarrangement or sticking.

which causes unreliability in their movement. It will be apparent at once that the present invention has overcome the disadvantages inherent in these previously disclosed arrangements.

To insure against the ring of the -fuse afterit has been charged and before the projectile has been red, there is provided a safety inertia element to lock the firing' hammer in a xed position. x

Referring to the drawings and particularly to Figs. 1 and 2, I represents the conical walls of the fuse secured to the core 2 in any conventional manner. In base 3, forming they lower part of core 2, is a cavity 4 in which slides a double 'ended 'firing hammer 5. At each end of cavity '4V are hollow screw plugs f6 which 'bear against shoulders 'I in base 3 and which hold .iiring caps 8 sfo positioned as to be struck by Passages 9 in screw plugs -6 com-` municate with passages I-I) in the base 3 which lead to a threaded cavity -II in the base 3 of the fuse. These passages and cavity are filled with powder I2.

`In the upper part o'f cavity H is a `screw plug I3 having a cavity I4 in which slides an inertia member I in which is a lug I-B 'engaging a reyducedlportion II of 'hammer 5. Inertia member I5 'is heldin `its engaging position by `a split wire ring 'I8 engaging groove I9 in the inertia member I5. vthe inertia 'member' lI5 from moving under `the Groove I3 i's made deep enough to preventv diaphragm is; placed in the fuse with its convex side toward the base 3 and on this side is secured a detent or head I'I by suitable means such as riveting or soldering. The detent I'I engages the reduced portion I'I of the hammer 5 and thereby holds it until the diaphragm is snapped to the reverse curvature as will" be explained later. I

The upper face of diaphragm 21 and the lower face'of flange 23 form a small chamber 28. The

outer surfaces of cylinder 22, the inner surfaces shocks of assembly, loading `and handling ofthe l under the effect of accelerationdue to 'ring In the lower part of cavity I I is a hollow screw plug 2l the inner and upper surfaces of which, together `with the walls of cavity II and the lower surface of plug I3 yform a space Vfor powder I2. Powder I`2'is in communication at the bottom of the fuse with the detonating charge of theprojectile (not shown).

The upper part `of core 2 consists vof amember made up of a hollow cylindrical portion V22 and a ilange 'portion 23. A threadedv plug 24 closes access to' the interior of cylinder 22. Cylinder 22 is secured air-tight tothe innersurfaces of the Walls I, as at 25, and flange 23 is screwed`4 into base 3. Walls I have an air-tightjoint with the base 3, as at 2S.

A diaphragm -21 is secured between shoulders at the lower outer edges of` flange v23 .and in the base w3. vAs already pointed out .the diaphragmVV of walls I and the upper surface of flange 23 form a large chamber 29 which is in communication with the under surface of diaphragm 2'I by passages 30 arid`3l, cavity 4, and grooves 32 in base 3. `The grooves 32 are concentric with the axis of the ycore and intersect a straight radial groove 32. (See Fig. 8.)

The bore of cylinder 22 is of two diameters,

.bore 33 in the upper portion and bore 34 in the lower portion. Bore .33 isslightlygreater than bore 34. Shoulder '3 5 is formed where Ithe two bores meet. n

In bore A33is cross-passage Valve 36, shown in elevation in Fig. 3. Valve 36 is cylindrical in shape with alongitudinal borey 3.1 in communication with a cross -bore .38, which cooperates with a port .3(9 lin thewalls of cylinder 22, `opening into chamber29. The axial rotation of valve 36 is adj-ustedfbylneans of a tool (not'shown) tting into `slot 40.1'Y The valve is held in .its longitudinal position by split wire ring 44I fitting into lagroove in' the inner walls of` cylinder 212 and a deep rgroove 42 'in the `outer surface of valve 36. In

the .lower portion of Valve 36 `is -an arcuate lug 43 shown .in cross-section -in Figs. 4 and .4a.

Just .below valve 35` and .abutting Yon the shoulder -35 is a solid stop mem-ber 44, shown in elevation in Fig. 5, whose outer diameter is such `that-iI-,Yhas `ad-riving tight t with bore 33. On the upper surface of stop 44 7is an arcuate lug 45 which, cooperating with lug 43, `limits the .axial rotation of lvalve :36. In fthe lower face `ofstop 44 is a groove 4Bwhich cooperates with passage 41 in the Walls of cylinder 2.2'to yconnect chamber V29 with .bore 34.

In bore z34is aspool-tlike valveconsisting of an upper cylindrical portion 48, a 'lower :cylindrical portion 49 both of which are of a diameter `sii-iiiciently `rless'fthahthat or bore v34430 permit axial movement of the-valve, as willfbe explained later. Between 'these cylindrical portions :is a -I reduced portion 5D. .In `-tlfie :lowenporti'on "4,9 is'lazftransverse cavityfcontaining Et'wo 1balls .'rI y@nlthe'lower end `of` the -valveis :an extensionfwhich limits 1the downward movementfof the'yalve and zat the sametime Vp'ern'iitseasy `access fof air to the bottom of the valve.,LTlie balls f5.1 `arefadaipt'ed to 'hold theilvalve its vupper position .by'their cooperating with fgroolve `v:in the Iwalls of bore T34 When'th'e'lvalve tis movedto'itsup-.per position and the balls are moved outward under;the acltion of centrifugal force --dire to rotation :o'ff'the projectile'wheni-tis' "t vlin the'wa'llsfoic der-T22 faretwo pairs `of passages iandfll. l? ssages 253 a re `in-.communicationfwithopening '55 Vin vthe nose v'of 'the lfuse, at their upper endsjwitli ports `56 inf-their ,central portion whichportsleardto bore 34, and with Vports 57 fat their y'lower ends which ports lead 'to "the" lower en d `Vofi'lo'orefGlL Passages v'554 arein vcom'munji'cation'vvitlfi bore 4434 at-ftheir upper ends throu'ghgports '53l and L are "intcommunication .at theirflow'er. ends 'with'chamb'er.`2j8. In the walls of cylinder "22 are radial passages '53 "which are so positioned along cylinder 22 as to be opposite the lower portion of reduced portion 50 when the valve is in its lower position, as shown in Figs. 1 and 2.

It will thus lbe seen that when the spool-like valve is in the position shown in Fig. 2, chamber 29 is in communication with chamber 28 by passages 59, ports 58 and passages 54. When the spool-like Valve is in its upper position, passages 53 are in communication with chamber 28 by ports 56, the-reduced portion i! of the valve, ports 58, and passages 54.

Operation- With the fuse assembled as shown in Fig. 2, with the cross bore 35 in communication with port 39 it is set to cletonate the projectile at a selected point in its trajectory by connecting the opening 55 in the nose of the fuse to a suitable source of air under pressure and charging chamber 29 through valve 36, cross bore 38 and port 3S, to a pressure, say ten pounds greater than the nose pressure on the fuse due to the velocity at the selected point in the trajectory. Air enters from chamber 29 to the top of the spool-like valve through passage 41 forcing it down so that chamber 29 is in communication with chamber 23 through passages 59, the reduced portion 5D of the valve, ports 58 and passages 54. Air also enters through passages 30 and 3l to cavity 4 where it is in communication with the lower side of diaphragm 21 through the grooves 32 and 32. The valve 36 is then turned from the position shown in Fig. 2 to that shown in Fig. l thus sealing chamber 29. The fuse is then disconnected from` the air charging source.

When the projectile is fired the initial nose pressure acting through passages 53 and ports 51 forces the spool-like valve upward thus placing the nose pressure on the upper surface of diaphragm 2l through ports 55, reduced portion 50 of the valve, ports 58, and passages 54. At the same time lug l5 is withdrawn, due to the inertia of the member I5, from engagement with the reduced portion I1 of hammer 5.

When the projectile has' reached the selected point in its trajectory and the fuse nose air pressure due to the velocity of the projectile has been reduced to ten pounds less than the pressure in chamber 29, the pressure in chamber 29 acting through passages 30 and 3|, cavity 4, and grooves 32 and 32', snaps over the diaphragm 21, to a curvature the reverse of that shown, this action pulls detent I1' with it and out of engagement with the hammer 5. Hammer 5 is then free to be moved outwardly under centrifugal force into contact with one or the other of firing caps 8. Upon the firing of caps `8, powder I2 is ignited which sets oi the detonating charge in the projectile.

It will -be understood that various changes may be made by those skilled in the art in the details of the embodiment of the invention disclosed in the drawings and described above Within the principle and scope of the invention as expressed in the appended claims.

We claim:

l. In a fuse for projectiles, the combination of a core and a firing cap therein, a ring hammer slidalble in the core and adapted to strike the ring cap, a diaphragm in the core, a detent connected to the diaphragm for holding the hammer in a iixed position, a chamber adapted to be charged to a predetermined air-pressure and in communication with one side of the diaphragm, an opening in the nose of the fuse, a loore in the core extending axially from the opening and in communication with the chamber through a port. valve means in the bore for controlling the port, a second axial bore in the core, a passage in the core in communication at its upper end with the opening and at an intermediate point with the second bore through a port, a second passage in the core in communication with the second 'bore through a port and with the other side of the diaphragm, a third passage providing communication between the second bore and the chamber. and a second valve means in theV second bore for controlling the two said ports associated. therewith and the said third passage, whereby in one position the second valve means places the second passage inY communication with the chamber through the said third passage and in another positionplaces the nrst two of said passages in communication with each other.

2. In a fuse for projectiles, the combination of a core and a firing Vcap therein, a ring hammer slidable in the core and adapted to strike the ring cap, a diaphragm in the core, a detent connected to the diaphragm for holding the hammer in a fixed position, a chamber adapted to be charged to a predetermined air-pressure and in communication with one side of the diaphragm, an opening in the nose of the fuse, a bore in the core extending axially from the opening and in communication with the chamber through a port, valve means in the bore for controlling the port, a second bore in the core, a passage providing communication `between the chamber and the said second bore, a second passage in the core in communication at its upper end with the opening and at its lower end and at an intermediate point with the second bore through ports, a third passage in the core in communication with Athe second bore at an intermediate point through a port and with the other side of the diaphragm, a fourth passage providing communication between the chamber and the upper end of the second bore, and a second valve means in the second bore operable in a downward direction b`y the air-pressure communicated from the chamber through the fourth passage and operable in an upward direction by the air-pressure communicated from the second passage through the port at its lower end, sai-d second valve means controlling the intermediate ports whereby in its lower position the third passage is in communication with the chamber through the first mentioned passage and in its upper position the second and third passages are in communication with each other.

3, In a fuse for projectiles, the combination of a core and a firing cap therein, a firing hammer slidable in the core and adapted to strike the firing cap, a diaphragm in the core, a detent connected to the diaphragm for holding the hammer in a fixed position, a chamber adapted to be charged to a predetermined air-pressure and in communication with one side of the diaphragm, an opening in the nose of the fuse, a bore in the core extending axially from the opening and in communication with the chamber through a port, valve means in the bore for controlling the port, a second bore in the core, a passage in the core in communication at its upper end with the opening and at an intermediate point with the second borethrough a port, a second passage in the core in communication with the second bore through a port and with the other side of the diaphragm, a third passage providing communicationk between the second bore and the chamber, a second valve means inthe -second bore controlling the two said portsassociated therewith and the said third passage whereby in one position the second yvalve means places the second passage in communication with the` chamber through the said third passage and in a second position places the rst two of said passages in communication with each other, and means for holding the second valve means inits second position when moved to that position.

4.,In a fuse` for projectiles, the combination` ,of a core and a firing cap therein, a firing hammer slidable inthe core and adapted to strike the firing cap, a diaphragm in the core, a detent connected to the diaphragm for holding the hammer in aV iixed position, a second detent slidable in the core, yieldable means for holding the second detent normally in engagement with the hammer, inertia operated means adapted to overcome the yieldab-lemeans upon the firing of the projectile and to move the second detent out of engage-ment with vthe hammer, a chamber adapted to be charged to a predetermined airpressure and in communication with one side of the diaphragm, an opening in the nose of the fuse, a Iborevin the core extending axially from the ropening and in communication with the chamber through a port, Valve means in the bore for controlling the port, a` second bore in the core, a passage in the core in communication at its upper end with the opening and at an intermediate point with the second bore in t'he core, through a port, a second passage in communication with the second bore through a port and .with the other side of the diaphragm, al

third passage providing communication between the second bore and the chamber, and a second valve means in the secondV bore controlling the two said ports associated therewith and the said third passage whereby in one position the second valve means places the second passage in communication with the chamber through-the said third passage and in a second position places the rst two of said passages in communication with each other. i

5. In a fuse for projectiles, the combination of acore and a ring cap therein, a ring hammer slidable in the core and adapted to strike the ring cap, a diaphragm in the core, a detent connected to the diaphragm for holding the hammer inl a fixed position, an vair chamber adapted to be charged to a predetermined pressure and in communication withrone vside of the diaphragm, an opening in the nose of the fuse, a b orein the core extending axially from the opening and in communication with the chamber through a port, valve means' in the bore for controlling the port, a stop inthe bore adapted to limit the motion and indicate the position of the valve means, Va second 4bore in the core, a passageI in the core in communication at its upper end with the opening and at an intermediate point with the second ibore through a port, a second passage in the core in communication with the second bore through a port and ywith the other side of thediaphragm, a third passage providing communication between the Asecond bore and the chamber, and a second Valve means in the second bore controlling the two said ports associated therewith and the said thirdpassage whereby in one position the second valve means places the second passage in `communication with the chamber throughA the said third passage and in another position places the first two of said passages in communication with each other.

6. In a fuse for projectiles, a ring cap having a hammer associated therewith, a detent for normally holding said hammer, a movable member for positioning said detent, said member having two opposing faces one of which forms a part ofthe walls of a first chamber adapted to be charged to a selected pressure, a second chamber formed in part by the ysecond face' of said member, valve means normally positioned to interconnect the said chambers, an opening in the nose of the fuse for obtaining a pressure dueto the velocity of the projectile, means actuated by the pressure due to theinitial velocity of the projectile for shifting said valveI means-to seal the iirst chamber at the selected pressure and to connect said opening `to said second chamber for applying the velocity pressure thereto, said movable member being operable to release `said detent from said hammer in response to a predetermined pressure differential resulting from a reduction in the pressure in the second chamber due to the decrease in the velocity of the projectile. I

THOMAS B. DOE.

ROBERT L. KENNGOT'I'. 

